These studies will use light scattering to probe the structures responsible for the transparency (and the loss thereof) of ocular tissues, especially the cornea. The approach is to use light scattering measurements to characterize corneas whose physiological conditions have been carefully controlled. Theoretical techniques are used to calculate the scattering expected from model structures and/or from the structures depicted in electron micrographs, and comparisons of the calculated and measured values test the validity of model structures and provide a measure of the influence of fixation procedures on the structures shown in electron micrographs. We have successfully employed these unique methods to show that the variation of scattering power with wavelength, in the visible spectrum, evidences a short ranged ordering of fibrils in normal rabbit stromas and the presence of regions void of fibrils in swollen stromas. One objective is to apply this same technique to other tissues, especially bovine and human corneas. Another important objective is to extract the structural information contained in the changes of light scattering with angle, which would have several advantages. Also, an apparatus with sufficient resolution to measure the depth dependence of scattering in near forward directions will be used to test the depth dependent features of the fibril structures revealed by electron micrographs of swollen corneas. Other objectives are determining the scattering due to the keratocytes, examining the extent to which light scattering affords a tool for studying the features of the fibril arrangement responsible for the transparency losses which occur in damaged corneas, and examining the extent to which light scattering measurements can be used to deduce the lamella-to-lamella variations in structure.